Firefighters in the Los Angeles area are slowly containing the Palisades fire, and local residents have started returning to some affected areas to sift through the rubble. Folks are finding their cars covered in this weird pink sludge, and they’re beginning to wonder: Is this bad?
Well, as it turns out, not really. Phos-Chek, the pink fire retardant that firefighters are dropping on LA County, is actually reasonably safe for cars. It’s noncorrosive, it washes off with regular soap and water, and even that bright pink dye will start to fade pretty quickly. The BBC found some advice about dealing with Phos-Chek:
Perimeter, the company behind Phos-Chek, has advised in the past cleaning the powder off as soon as it is safe to do so.
“The longer the retardant dries, the more difficult it is to remove completely,” they cautioned.
Perimeter doesn’t advise using a pressure washer, as one could push Phos-Chek into more porous materials, but the company claims all its retardants are “completely water soluble.” Phos-Chek should be removed quickly, to prevent it from forming a difficult-to-remove film, but it’s not going to eat away at your car. It’s intentionally designed not to, actually.
Phos-Chek is designed to be dropped from helicopters and airplanes, both of which are nearly always made of metal. Thus, the powder — the U.S. Forest Service specifically uses Phos-Chek MVP-Fx — contains corrosion inhibitors to keep the planes and copters it’s in from breaking down. It’s slightly saline, but far less so than the road brine used to keep salt off wintry streets. But what else is in that powder? Could that be bad?
According to the material safety data sheet for Phos-Chek MVP-Fx, the powder is primarily composed of monoammonium phosphate, the same flame retardant you’d find in a dry chemical fire extinguisher. Monoammonium phosphate is somewhat corrosive, but that’s likely what Phos-Chek’s corrosion inhibitors are there to mitigate. The solution is also relatively acidic, comparable to your reference standard bird shit, but that can be neutralized with an alkaline cleaner.
All in all, Phos-Chek may not be fantastic for your paint, but it’s not much worse than anything else that’s likely to land on your hood. Wash your car as you normally would, just save the pressure washer for after your first soap and rinse — and be thankful you’ve still got a car to wash at all.